Pereira S, Pun T
Geneva Univ., Switzerland.
IEEE Trans Image Process. 2000;9(6):1123-9. doi: 10.1109/83.846253.
Digital watermarks have been proposed as a method for discouraging illicit copying and distribution of copyrighted material. This paper describes a method for the secure and robust copyright protection of digital images. We present an approach for embedding a digital watermark into an image using the Fourier transform. To this watermark is added a template in the Fourier transform domain to render the method robust against general linear transformations. We detail a new algorithm based on polar maps for the accurate and efficient recovery of the template in an image which has undergone a general affine transformation. We also present results which demonstrate the robustness of the method against some common image processing operations such as compression, rotation, scaling, and aspect ratio changes.
数字水印已被提议作为一种抑制受版权保护材料的非法复制和传播的方法。本文描述了一种用于数字图像的安全且稳健的版权保护方法。我们提出了一种利用傅里叶变换将数字水印嵌入图像的方法。在这个水印上，在傅里叶变换域中添加一个模板，以使该方法对一般线性变换具有鲁棒性。我们详细介绍了一种基于极坐标图的新算法，用于在经过一般仿射变换的图像中准确且高效地恢复模板。我们还展示了该方法针对一些常见图像处理操作（如压缩、旋转、缩放和宽高比变化）的鲁棒性结果。
